Brain Constructs Reality Through Active Sensory Editing

Key Quotes

"If you don't know what tinnitus is it's like that ringing you hear in your ears after getting out of a loud concert but it's all the time the din of the tinnitus is just constantly going on it's like man's search for meaning basically but in your brain"

The host, Jonquilyn Hill, introduces tinnitus by comparing it to the temporary ringing after a loud event but emphasizes its persistent nature. Hill frames this constant sound as analogous to humanity's "search for meaning," suggesting it represents a fundamental, albeit internal, struggle within the brain.

"basically in your ear there's fibers that respond to soft sounds and there's fibers that respond to loud sounds so that means there's fibers that respond to whispers or kind of the asmr stuff and then there's fibers that really get activated if you're crossing the street or you're in an airplane or a vacuum cleaner or something and on a hearing test what they do is they put you in this you know soundproof room the audiologist sits next to you says raise your hand whenever you can hear a beep and the beep gets softer and softer and softer until you can't hear the beep and what they're doing is just testing the soft fibers they're just testing if you can hear the quietest possible noise and if you can hear the quietest possible noise they say hey your hearing is fine but that doesn't test damage that could happen to the loud fibers"

Scientist Stefan Maison explains the concept of "hidden hearing loss," detailing how standard hearing tests only assess the fibers sensitive to soft sounds. Maison points out that damage to fibers that respond to loud sounds, which can lead to conditions like tinnitus, goes undetected by these tests.

"now what happens in your brain is your brain is kind of doing a similar thing for sound but when some of the nerve fibers are damaged you're getting less input than the brain would expect and so it's kind of like turning on the heat so to speak but it can't get the sound that it needs so it kind of creates its own sound to fill in that gap oh these neurons like sensitize themselves they're like oh i need to make my activity level go back to where it's supposed to be i'm going to swap out different parts and make myself more sensitive to excitatory inputs so now you start to perceive a sound that is not there"

Researcher Dan Polly likens the brain's response to damaged auditory nerve fibers to a climate control system. Polly explains that when the brain receives less auditory input than expected, it compensates by generating its own sound to fill the perceived gap, a process where neurons become more sensitive to create this internal signal.

"so our brain has a superpower how do we use it for good that's up next support for the show comes from givewell givewell is an independent resource that offers transparent research about great giving opportunities they spent 18 years researching global health and poverty alleviation and they say they only direct funding to the highest impact opportunities they've found here are some examples of what donations to givewell's recommended charities can achieve bed nets and preventative medication to reduce outbreaks of malaria distributing vitamin a supplements to reduce deficiencies and save lives and cash incentives for routine childhood vaccines over 150 000 donors have already trusted givewell to direct more than two and a half billion dollars and according to givewell rigorous evidence suggests that these donations will save over 300 000 lives and improve the lives of millions more you can find all their research and recommendations on their site for free to make a tax deductible donation today go to givewell org and pick podcast and enter explain it to me at checkout make sure they know that you heard about givewell from explain it to me again that's givewell org to donate or to find out more"

The host, Jonquilyn Hill, transitions from discussing the brain's "superpower" of perception to a sponsorship message. Hill introduces GiveWell as an organization providing research on high-impact charitable giving opportunities, highlighting their work in global health and poverty alleviation.

"so the question is does your brain basically create a matrix for you what is real how do you define real so you're not seeing reality unfiltered you're just living in the matrix like literally if you're talking about what you can feel what you can smell what you can taste and see then real is simply electrical signals interpreted by your brain so it's this idea that our senses are subjective correct because everything that you perceive is filtered through your sensory organs and then goes through your brain and if we assume that you have a unique brain which i do then you're bringing a lot of yourself to what you experience"

Professor Pascal Wallach discusses the brain's role in constructing our perception of reality, likening it to a "matrix." Wallach explains that what we perceive as real is ultimately electrical signals interpreted by our individual brains, making our sensory experiences subjective.

"what we could show is that it has to do with your assumptions about lighting if you assume the thing was backlit or in a shadow or illuminated by white light bright light let's say sunlight it would be white and gold and if you assume it was artificial light or inside then you would see it as black and blue and that has to do with what you have seen more of so if you're like a night owl you've seen more artificial light by the way just to be clear it's not gonna be true for everybody because this lifestyle is only a proxy for light exposure but something we can measure"

The speaker explains the phenomenon behind the "The Dress" illusion, where perception of color depends on assumptions about lighting. The speaker states that if one assumes the dress was lit by sunlight, they see it as white and gold, whereas assuming artificial light leads to seeing it as black and blue, linking this to an individual's past light exposure.